Four independent 1000/100/10Mbps RJ45 ports on a single PCIe x1 card purpose-built for pfSense / OPNsense firewall appliances and OpenWrt soft routers.; Four dedicated Realtek RTL8111H controllers, one per port, keep multi-WAN routing stable with low CPU load.; Plug and play on Windows 10/11 and modern Linux; natively recognized by pfSense, OPNsense, OpenWrt and Proxmox; VMware ESXi 5. x/6. x supported.; IEEE 802.1Q VLAN tagging and 802.3 x flow control supported ideal for multi-WAN, VLAN segmentation and network isolation.; Standard + low-profile brackets included fits full towers, SFF desktops and slim firewall chassis; works in x1/x4/x8/x16 slots.